A Book on General Image Editing Concepts?

halftrack asks: "Someone I know wanted 'Photoshop for Dummies' for Christmas because she wanted to learn how to use it properly (who hasn't struggled trying to draw a simple line?) However, having a strong disliking for any sort of vendor lock-in I went searching for a book that would teach image editing without tying it too strongly to Photoshop (or Gimp for that matter). However, all my searches turned out blank. Thus I was wondering if there exists such a book, or is the field too diverse? The ideal would be a (thick) book that would cover the basic concepts (layers, paths, selections, channels etc.,) before presenting how these concepts are implemented in different applications. Such a book should provide the reader with a portable skill-set and give her/him the ability to objectively choose the right tool for the job, at the right cost. Does this book exist?"

Comments

Re:Seems to me...

[Arandir]

There are tons of filters for image processing, but I'll be damned if I know what they all mean. Instead of telling us which buttons to push in Photoshop, maybe they could stop and tell us the concepts behind them. What exactly is a convolution matrix? What is an unsharp mask? What's a gaussian blur? What is laplace edge detection? Etc, etc.

Filters are but one example. I would also like to know how to lighten an underexposed picture without making it look washed out. And other things like that.